A polarizing plate is useful as an optical component forming a liquid crystal display device. As a polarizing plate in the art, those having a constitution of laminating a protective layer including a transparent resin film on one surface or both surfaces of a polarizing film using an aqueous adhesive and the like have been used.
As such a transparent resin film, a triacetyl cellulose film (TAC film) has been much used due to its excellent optical transparency or moisture permeability. The polarizing plate is adhered to liquid crystal cells through other optical functional layers as necessary using a gluing agent, and is inserted to a liquid crystal display device.
As a polarizer used in the polarizing plate, a uniaxially extended PVA-based film dyed with iodine is much used, and since it is thin and has poor strength, a protective film is required. However, a TAC film, a polarizer protective film that has been normally used in the art, does not have favorable moisture-heat resistance, and has weak pencil hardness and scratch resistance properties, and separate hard coating is required.
A TAC or acrylic film of a lower polarizing plate of a display faces a diffuser, a prism film or a DBEF film in a backlight unit. Displays become thinner and larger nowadays, and accordingly, a gap between a lower pol and a BLU decreases and lower polarizing plate sagging occurs causing a branching phenomenon of the protective film (TAC, acrylic film) of the lower polarizing plate, and as a result, luminance non-uniformity occurs declining product qualities.
In addition, a protective film for protecting a base film such as TAC/acryl is required when working a polarizing plate, and static electricity may occur when removing the protective film of the lower polarizer in an assembly stage of a final product, and it may damage circuit components. Accordingly, a protective film having an antistatic function needs to be used in order to provide an electro static discharge (ESD) preventing function, which leads to a problem of a process cost increase.
Accordingly, development of a polarizing plate capable of enhancing product qualities by minimizing static electricity generation while reducing process costs has been urgently required.